1. Field of the Invention
The present invention relates to an image analysis using a remote sensing image, and in particular, a computer-aided image interpretation technology.
2. Description of the Related Art
Various features exist in images (hereinafter described as the remote sensing image) shot by platforms such as aircrafts, helicopters, balloons, artificial satellites, and etc. It is described as a visual interpretation, an image interpretation or simply an interpretation, to distinguish these features by manpower.
It is possible to obtain various information by visual interpretation of the remote sensing image. For example, the remote sensing image obtained from the sky in the region struck by an earthquake, a fire, etc. is very useful to grasp the situation of damage due to the characteristics of wide area and the volume of information. Moreover, it is possible to regularly observe the amount of marine traffic by interpreting the remote sensing image obtained by taking a picture of harbors and high seas. Moreover, a road map and a railway map can be made by interpreting the remote sensing image obtained by taking a picture of the region including a road and a railway. Moreover, the construction situation of the road can be understood by taking pictures of the same region several times by staggering the time of taking pictures, obtaining the remote sensing image, and extracting the difference between those images. In addition, it can be used for the index to calculate urbanization rate, farmland rate, and etc. by seeing the regularity degree of the structure of the features. Moreover, it can be used for fire simulation, transition of urbanization development, city planning, etc.
Such interpretation work is performed by displaying the remote sensing image on the display of a computer, visually interpreting the feature, superimposing the name of feature that shows the kind of individual feature on the remote sensing image, and filling it in. Alternatively, it is possible that the remote sensing image can be printed on a medium such as paper, so as to be visually interpreted, while the result can be filled in on the paper, and thereafter an interpretation result is digitized.
So far, the following methods have been proposed as a method to do such interpretation work efficiently. That is, there is a method of efficiently proceeding the interpretation work that uses the effect of the afterimage of a human's eye, by preparing the remote sensing image and the interpretation result for the remote sensing image, and alternately displaying (what is called, flicker-displaying) the image and the interpretation result at the time interval of several seconds (For example, see JP-A-2001-338292).
Moreover, a method of automatically classifying the feature in the remote sensing image (hereafter, automatic classification) is proposed referring to one of spectral characteristics, radiometric characteristics, and diffuse characteristics, textures and shapes or using the technologies in which these are combined (for example, JP-A-2001-307106). As the result of the automatic classification, it is understood which feature exists in which position of the remote sensing image. This result is used to replace the interpretation work. In the method disclosed in the above-mentioned document, the automatic classification with higher accuracy has been achieved by changing the extraction algorithm and the parameter of the feature in each kind of features. Moreover, a method is disclosed that obtains several classification results referring to several feature extraction algorithms, and are output in descending order of likelihood (accuracy) of the classification result at the end, when the kind of feature is not known.